Phenotypic Methods for Detection of Carbapenemase Production in Carbapenem-Resistant Organisms: What Method Should Your Laboratory Choose?

Antimicrobial resistance is a rising problem among Gram-negative organisms, and resistance to carbapenems is a special concern and an urgent public health threat. Rapid detection of carbapenem resistance, and carbapenemase production specifically, is becoming increasingly important for guiding infection control strategies and for therapeutic management of patients. Several types of phenotypic tests for the detection of carbapenemase production continue to be developed and include culture/growth-based methods (carbapenem inactivation method [CIM]/modified CIM [mCIM]), colorimetric assays (Carba NP and derivatives), matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based tests, and lateral-flow assays. Here, we describe the tests currently available, their performance characteristics, and how to select and verify/validate a test for the specific needs of a laboratory.